Simple songs leave you no place to hide. Having a verse, verse, chorus, verse, chorus, bridge, solo, bridge, chorus, verse, chorus end can be much easier than something straightforward.
recently did “Don’t Get Me Wrong” . Took me to the last rehearsal to nail it. Even then, the “fast G” meant I stared at the guitarist for a cue!
Once did a Country n Western set as a favour. Sweating buckets at playing 1/5 all nigh5 and hittin* my mark!
Ginal easy song….sing Purple Rain….the gaps for the singer! Ended up counting her in at times.